www.nature.com/scientificreports OPEN Multi‑center clinical study using optical coherence tomography for evaluation of cervical lesions in‑vivo Chenchen Ren1, Xianxu Zeng2, Zhongna Shi1, Chunyan Wang3, Huifen Wang4, Xiuqin Wang5, Baoping Zhang6, Zhaoning Jiang7, Huan Ma7, Hao Hu7, Haozhe Piao3, Xiaoan Zhang8* & Baojin Wang1* In this prospective study of an in‑vivo cervical examination using optical coherence tomography (OCT), we evaluated the diagnostic value of non‑invasive and real‑time OCT in cervical precancerous lesions and cancer diagnosis, and determined the characteristics of OCT images. 733 patients from 5 Chinese hospitals were inspected with OCT and colposcopy‑directed biopsy. The OCT images were compared with the histological sections to fnd out the characteristics of various categories of lesions. The OCT images were also interpreted by 3 investigators to make a 2‑class classifcation, and the results were compared against the pathological results. Various structures of the cervical tissue were clearly observed in OCT images, which matched well with the corresponding histological sections. The OCT diagnosis results delivered a sensitivity of 87.0% (95% confdence interval, CI 82.2–90.7%), a specifcity of 84.1% (95% CI 80.3–87.2%), and an overall accuracy of 85.1%. Both good consistency of OCT images and histological images and satisfactory diagnosis results were provided by OCT. Due to its features of non‑invasion, real‑time, and accuracy, OCT is valuable for the in‑vivo evaluation of cervical lesions and has the potential to be one of the routine cervical diagnosis methods. Cervical cancer is one of the most common malignant tumors of the reproductive system in women. It is one of the main gynecological tumors causing female death with a low 5-year survival rate1. Clinical reports show that the global incidence and mortality rate of cervical cancer is 6.6% and 7.5%, respectively, while 85% of cervical cancer cases are in developing countries2. At present, the incidence of cervical cancer shows a trend of getting younger. Studies show that the development of cervical cancer needs a relatively long time from several years to decades, including the vital stage of cervical intraepithelial neoplasia (CIN). So early screening and treatment of precancerous lesions play important roles in preventing cervical cancer 3. Te wide application of efective cervical cancer screening in developed countries has led to a signifcant reduction in cervical cancer incidence4. Currently, there are several clinical screening and diagnosis methods to identify patients with precancerous lesions, including Pap smear, human papillomavirus (HPV-DNA) test, TinPrep liquid-based cytology test (TCT), colposcopy, and cervical biopsy. As the earliest cytological test method, Pap smear has been gradu- ally replaced by TCT due to its low accuracy, although it costs much less5. HPV tests have been widely used in clinical practice. HPV test has a high sensitivity but a low specifcity, which leads to a fairly high rate of false positives6,7. High sensitivity means that HPV tests can reduce the occurrence of missed diagnosis, but too many misdiagnoses occur because HPV infections can be transient and may not develop to cervical epithelial lesions in most cases. TCT is also widely used in clinical practice as a cervical cytology testing technique, which has a higher specifcity than the HPV test. However, it has a much lower sensitivity for CIN detection compared with 1Department of Gynecology, The Third Afliated Hospital of Zhengzhou University, Zhengzhou 450052, China. 2Department of Pathology, The Third Afliated Hospital of Zhengzhou University, Zhengzhou 450052, China. 3Department of Gynecology, Liaoning Cancer Hospital and Institute, Shenyang 110042, China. 4Department of Gynecology, Luohe Central Hospital, Luohe 462000, China. 5Department of Gynecology, Puyang Oilfeld General Hospital, Puyang 457001, China. 6Department of Gynecology, Zhengzhou Jinshui District General Hospital, Zhengzhou 450002, China. 7Zhengzhou Ultralucia Medical Technology Ltd., Zhengzhou 450016, China. 8Department of Imaging, The Third Afliated Hospital of Zhengzhou University, Zhengzhou 450052, China. *email: [email protected]; [email protected] Scientifc Reports | (2021) 11:7507 | https://doi.org/10.1038/s41598-021-86711-3 1 Vol.:(0123456789) www.nature.com/scientificreports/ Figure 1. Ultralucia OCT cervical scanning system and handheld probe. the HPV test8. Factors such as infammation, unsatisfactory sampling, and lack of experience of a cytologist may all lead TCT to a missed diagnosis. Colposcopy is a visual inspection method utilizing the magnifcation function of a colposcope. It gives a direct-viewing impression of the cervix, but its accuracy relies heavily on the experience of the investigators. A study shows that the sensitivity of conventional colposcopy was merely 55%9. Colposcopy-directed biopsy with histopathological confrmation is the current gold standard for diagnosing cervical diseases, but biopsy is invasive and may cause bleeding and infection. Moreover, since only a few cervical locations can be selected for biopsy, the chance of missed diagnoses of high-risk lesions is as high as 37%10. Optical coherence tomography (OCT) is a 3-dimensional (3-D) imaging technology frst developed in the 1990s11. Based on the principle of low coherent light interference, the imaging of superfcial biological tissue is carried out by detecting the interference signal formed by a reference light and back-scattered light from diferent depths of the sample. Afer the back-scattered light signal is detected and processed, 3-D images of the internal tissue microstructures can be obtained. Te axial resolution of ~ 1–10 μm can be generally reached, while the transverse resolution can also reach a few microns12. OCT can detect tissue structures with a penetration depth of 1–2 mm13. Although the imaging depth is relatively shallow compared to other clinical imaging methods, such as ultrasound, MRI, and CT, the resolution of OCT in tissues is 50–100 times higher than that of ultrasound, far higher than the resolution of MRI and CT. With its advantages of high resolution, rapid imaging, and non- invasiveness, OCT has attracted much attention in clinical applications. Currently, it has been widely applied to examinations of ophthalmic14, cardiovascular15, and oral diseases16. In a previous study by Zeng et al., an optical coherence microscopy (OCM) system was used to analyze the image features of cervical tissue and it demonstrated satisfactory diagnosis results in a 2-class classifcation analy- sis with ex-vivo cervical tissues17. In this study, we performed a multi-center clinical study to obtain OCT images of in-vivo cervical tissues. By comparing the OCT images with corresponding histological images, the optical features of various categories of in-vivo cervical lesions were summarized. Ten, the OCT diagnosis results were analyzed, and the clinical application value of OCT on the diagnosis of in-vivo cervical lesions was discussed. Methods Clinical OCT system. Te OCT system adopted in this study is Ultralucia OCT Cervical Scanning System (model: UL-C100) developed by Zhengzhou Ultralucia Medical Technology Co., Ltd. Tis device is equipped with a broadband light source with a central wavelength of 850 nm and a full width half maximum (FWHM) bandwidth of > 155 nm, providing an axial resolution of < 5 μm and a transverse resolution of < 10 μm in tissue. A handheld probe (shown in Fig. 1) was used to deliver the imaging beam to the surface of the cervix. Te optical power of the probe output beam is less than 5mW. Te outer diameter of the probe is ~ 10 mm, making it easy to pass through the speculum. Te maximum scanning speed is 80,000 A-scans/s, and the imaging depth is ~ 1 mm. In our study, a circular scanning mode is adopted for image collection. Considering the optical beam size and the focusing-defocusing efect, the scanning diameter can be adjusted within the range of 0–2 mm according to the setting. Compared to the traditional linear scanning mode, the circular scanning mode can obtain a much wider scanning range with the thin imaging probe, allowing more tissue information to be collected in each frame of the OCT image. In this study, the number of A-scans per frame is set to 1200 to maintain sufcient pixel density and the image resolution. Te scanning diameter is 0.9 mm (the inner circle) to 1.1 mm (the outer circle). 10 circular scans were performed in the annular region, with equal intervals between adjacent circles. Scientifc Reports | (2021) 11:7507 | https://doi.org/10.1038/s41598-021-86711-3 2 Vol:.(1234567890) www.nature.com/scientificreports/ Hospital No. of patients Age (mean ± SD) HPV results TCT results Positive: 281 Positive: 215 Te Tird Afliated Hospital of Zhengzhou University 350 38.67 ± 9.86 Negative: 31 Negative: 63 Untested: 38 Untested: 72 Positive: 138 Positive: 69 Liaoning Cancer Hospital and Institute 227 44.08 ± 8.38 Negative: 84 Negative: 134 Untested: 12 Untested: 24 Positive: 39 Positive: 39 Puyang Oilfeld General Hospital 59 43.03 ± 8.06 Negative: 3 Negative: 12 Untested: 17 Untested: 8 Positive: 49 Positive: 36 Luohe Central Hospital 57 40.37 ± 10.05 Negative: 8 Negative: 21 Untested: 0 Untested: 0 Positive: 36 Positive: 9 Zhengzhou Jinshui District General Hospital 40 39.03 ± 12.47 Negative: 2 Negative: 27 Untested: 2 Untested: 4 Positive: 536 Positive: 368 Overall 733 40.85 ± 9.79 Negative: 128 Negative: 257 Untested: 69 Untested: 108 Table 1. Patient demographic information. Study plan and examination process. Te study was approved by the Ethics Committee of the Tird Afliated Hospital of Zhengzhou University, the Ethics Committee of Liaoning Cancer Hospital & Institute, the Ethics Committee of Puyang Oilfeld General Hospital, the Ethics Committee of Luohe Central Hospital, and the Ethics Committee of Zhengzhou Jinshui District General Hospital. All research was performed in accord- ance with relevant guidelines/regulations. Informed consent was obtained from all participants and/or their legal guardians.